Known in the art is an electronic musical instrument which provides model pieces of music for a user to select a model piece of music and practice playing the selected piece on the musical instrument. The user is to practice the musical instrument by judging which notes to play according to the notes printed on a sheet music. The performance is (i.e. the played notes are) compared with the model music piece in data, and the result of the evaluation is to be shown on the display device of the electronic musical instrument.
In such a system, however, the model music data as the reference for comparison is performance data for playing back tones for an actual performance including musical expressions (i.e. emotions). The tone generation time points and durations of the respective notes may be different from the indicated notes on the music score to some extents, accordingly. Consequently, even though the user plays every note exactly in view of the music score, the played notes may not necessarily coincide with the notes in the model performance data so that the evaluation will not be very good sometimes.
There is another type of electronic musical instrument for practice, which provides guide lamps on the keyboard. The user is to follow the lighting guide lamps to know which notes to play for inputting performance data. But, as long as the model music data as the reference for comparison is the music data for playing back tones for performance as described above, a beginner will find difficulty in practicing performance according to such model music data as a reference for practice.
In this connection, the performance guide data may be separately composed by modifying the performance data which have been prepared particularly for playing back tones, or may be stored in a separate track exclusively provided for the playing guide, as known in the art, for example, as disclosed in unexamined Japanese patent publication No. H10-69732. However, the correspondence or concurrence between the guiding data and the music sheet notation is not taken care of precisely, the user will be perplexed as to which to follow, the guiding lamps or the printed notes on the sheet music.
Thus, there will be some inconveniences in practicing performance (i.e. musical instrument play) following the performance data prepared for playing back tones of the model music piece in either of the above cases.
FIG. 6 shows the relations between the printed notes on the sheet music and the performance data prepared for playing back tones. For example, in the case where there is an eighth note at the top of a measure on the music score as shown at part (a) of FIG. 6, the performance data corresponding to the music score notation should have a duration starting at the time point of the top of the measure and ending at the time point half way to the next beat to coincide with the position of the displayed note, as shown at part (b) of FIG. 6. In an actual performance, however, there may be a situation, as shown at part (c) of FIG. 6, where the starting time point of the note comes a bit earlier than the bar line (the top of the measure) with a musical emotion added at least to the starting time point of the note. In such a situation, there may arise an inconvenience that such a note at the top of the measure according to the music score may not be included among the played-back tones of the repetition span for practice, when the practice is repeated with respect to a span having such a measure at the top of the span.
As explained above, there may be various problems in practicing the instrument performance, where the model music data is the performance data prepared particularly for playing back the performance tones.